Don't pick a bad pineapple or a mealy watermelon again. Know the secrets to fresh and ripe foods before you go wrong at the produce aisle. The kitchen mavens at Stack Exchange provide tips on selecting the freshest fruits and vegetables.

Meyer lemons should be quite a bit softer than a standard Eureka lemon, because the skin is much thinner. That said, it shouldn't be like a gentle squeeze causes your finger to sink in 1/2 an inch. If that happens, I think you've found a batch that are too old and have started to get mushy or lose moisture. Keep looking for good ones - Meyer lemons are terrifically fragrant, floral and mild.

Red bananas change color, just not so obviously as normal bananas. There's a slight greenish tint that disappears as they ripen, and the red becomes a bit deeper (some people say purplish).

Red bananas also get softer - including the skin getting more tender, just like yellow banana skin. Just think about how bananas feel when ripe, feel your red bananas, and (perhaps with a tiny bit of trial and error) you can figure it out.

Smell. Really, this is the most reliable criterion for practically any fruit.

I have had occasions when I entered a supermarket to quickly buy one thing, aimed at the correct aisle, but when the smell of good strawberries reached me near the produce, I turned and added a pack of them. I have never been disappointed with such strawberries. Also, if you smell the slightest hint of mold, fermentation, or foulness, you know they may not keep even one night.

Another sign is that a ripe strawberry will be red through and through. A strawberry picked underripe will be white or even slightly greenish at the top. It doesn't taste good then. But this is a negative sign, because not all red strawberries taste good.

Don't ever go by shape. The tastiest sort of strawberries my grandparents grew produced ugly, lumpy strawberries of a light, slightly orange color. They also had a few rows of a sort which produced perfectly conical, deep red strawberries, they looked like an advertisement - but they were hard and dry, and didn't have much aroma. Probably, there are some strawberries which both look and taste good - just don't think that looks or color predict a good strawberry, because they are independent.

Colour: There are many different varieties of mangos. Some go from green to red. Some end up orange Some start off yellow and end up orange. So once you're familiar with the type of mango you're buying, you can get an idea of what a ripe one looks like.

Smell: A ripe mango will smell sweet. Check near the stem end, the smell should be stronger there. You should smell it and think "mango." Smell is a large part of your taste, so it should be very familiar.

Firmness: Mangos, like peaches will soften as they ripen. Just as it starts to go from firm to soft, it is just about ripe.

Weight: With most fruit you can tell their ripeness by their weight. A riper fruit will be slightly heavier than an unripe one.

As an aside, if you're at a grocery store, and you see a few different types of mangos, look for these Ataulfo mangos: They're my personal favourite. The flavour is richer, and they are a lot less stringy.

I don't believe there is a fool-proof way to determine 'ripeness' without taking a slice out of a watermelon. The best you can do is look for certain signs:

Ripe melons have a hollow sound when you tap or slap the outside

Look for the patch where the melon would have been on the ground (called the field spot). If it's a yellow colour its probably ripe. If it's white, it's probably not.

It should feel relatively heavy when lifted

Weird areas on the skin aren't necessarily bad. Insects may have tried to start eating the fruit because it is ripe, but have only marred the surface.

Unfortunately, melons don't continue to ripen once picked, unlike fruits such as apples and bananas, which contain ethylene. As a tip, don't store melons with these kinds of fruit, they may well go 'soggy.'

A very fresh, ripe ear of corn will have a moist, green, unblemished husk; when peeled back, its silk will also moist and clinging to the kernels. In the store, you may find that an ear of corn will have a slightly dried out husk, but if it's still green and the kernels look plump when the husk is pulled back, that ear's fine. Ignore any husks that are very dry with rotten-looking, off-smelling silk tops.

If you can squish an avocado in your hand, it's much too ripe. Everyone else has had a squish of this avocado, and it's been manhandled.

Depending on the variety in your supermarket (In Australia, we usually get Hass Avocados, which go from a green colour to a black colour), you want one that's still firm when you buy it, and after a few days in the fruitbowl with the apples, it will become a nice constancy: still not completely soft to touch, but you can't play football with the thing anymore.